KOS-MOS wasn't truely in Soul Calibur III like Link, Heihachi and Spawn were in II or Yoda, Vader and Vader's Apprentice in IV or Ezio was in V. However, you could unlock pieces of her costume to make a character to look like her in Soul Calibur III.
Everyone misses Taki, period. Her gorgeous, flowing moves; her fierce and determined demeanour; her catsuit that seemed to be painted on over those impressive boobs...